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We present a novel electrochemical cell lysis device to prepare DNA samples for lab-on-a-chip (LOC) applications. It utilizes the electrolysis of saline solution to generate hydroxide ions (OH(-)) at the cathode as alkaline lytic agents. Cathode and anode chambers are separated by a negatively-charged ion exchangeable polymer diaphragm to maintain the high(More)
We have developed a bead-packed microfluidic device with a built-in flexible wall to automate extraction of nucleic acids from methicillin-resistant Staphylococcus aureus (MRSA) in nasal swabs. The flexible polydimethylsiloxane (PDMS) membrane was designed to manipulate the surface-to-volume ratio (SVR) of bead-packed chambers in the range of 0.05 to 0.15(More)
During screening for the flavonoid chemosensitizers, it was found that 5,7,3',4',5'-pentamethoxyflavone (PMF) was equipotent to verapamil in vitro with respect to the chemosensitizing effect. PMF appears to have a chemosensitizing effect not only by increasing the intracellular accumulation of the drugs without competition in a binding site of azidopine but(More)
We have developed a miniaturized bead-beating device to automate nucleic acids extraction from Gram-positive bacteria for molecular diagnostics. The microfluidic device was fabricated by sandwiching a monolithic flexible polydimethylsiloxane (PDMS) membrane between two glass wafers (i.e., glass-PDMS-glass), which acted as an actuator for bead collision via(More)
DNA metabolic processes such as DNA replication, recombination, and repair are fundamentally important for the maintenance of genome integrity and cell viability. Although a large number of proteins involved in these pathways have been extensively studied, many proteins still remain to be identified. In this study, we isolated DNA-binding proteins from(More)
A di(2-ethylhexyl)phthalate (DEHP) was accidentally extracted from plastics in the process of purification of chemosensitizers reversing P-glycoprotein (Pgp)-mediated multidrug resistance (MDR). The purpose of this study was to investigate the Pgp-reversal activities of phthalates, which are endocrine-disrupting chemicals, by utilizing the(More)
Microfluidic devices for on-chip amplification of DNA from various biological and environmental samples have gained extensive attention over the past decades with many applications including molecular diagnostics of disease, food safety and biological warfare testing. But the integration of sample preparation functions into the chip remains a major hurdle(More)
Most of the widely used RNA isolation methods involve the use of toxic chemicals, including chaotropic salts and phenol. In an effort to solve this problem, we studied an alternative method to purify total RNA without any harmful chemicals. This method was based on silica spin columns and kosmotropic Hofmeister salts. The RNA yield was comparable to that of(More)
A novel bacterial DNA sample preparation device for molecular diagnostics has been developed. On the basis of optimized conditions for bacterial adhesion, surface-modified silicon pillar arrays for bacterial cell capture were fabricated, and their ability to capture bacterial cells was demonstrated. The capture efficiency for bacterial cells such as(More)
A method in which an electrode itself is used as the sample preparation microchip is described. The gold electrode was coated with an ion-permeable polymer, Nafion, to prevent the permanent adsorption and destruction of DNA. The modified electrode was able to capture as much DNA as the bare gold electrode and to release the captured DNA effectively, whereas(More)